Hydraulic control oil ring



F. D. I 'RISBY. ETAL I HYDRAULIC CONTROL OIL RING Aug. 3, 1948;

Filed May 3, 1945 mmvroa Frank 0. f'rzsbz 01' file/um M Mar/en Patented Au 3, 1948 masonic comer. on. ma

Frank D. l rilbyand Melvin W.

' Mo., .aocignors to Marion, St. Louis.

Ramsey Accessories Manufacturing Corporation, St. Louis, Mo., a corpo- Mluourl ration of Application as, a. 1945, Serial N... 591,671

.1 Claim. (circa-44) Our invention has relation to improvements in oil sealing rings for hydraulic control activatin pistons (such as employed in hydraulic brakes) and it consists in the novel features of construction more fully set forthin the specification and pointed out in the claim.

The invention is directed primarily to a com- POsite-type of ring employing both rubber (or an equivalent material) and spring steel, cast iron .or plastic operating as a unit to prevent leakage of oil past the piston and thus maintain the maximum operating pressure. It has for its principal objects the provision of an efl'ective sealing ring that will have a long life and exert a high unit pressure on .the cylinder wall and be operative over an extremely wide temperature range. Other advantages will be better apparent from a detailed description of the invention in connection with the accompanying drawings, in which Figure 1- is a longitudinal middle section of a conventional type hydraulic oil control cylinder and piston (partly in elevation) equipped with our improved sealing rings; Figure 2 is a'sideview of the sealing ring at the high pressure end of the piston; Figure 3 is an edge view thereof; Figure 4 is an enlarged cross section taken on the line 4-! of Figure'ii; Figures 5 and 6 are cross section views on the order of Figure 4 but of modified forms of sealing rings.

Referring to the drawings, and for the present Figures 1 to 4 inclusive, C represents a hydraulic control cylinder in which a piston P operates under hydraulic pressure obtained in any well known manner. The eifectiveness of the piston P as an activating device depends, essentia1ly,'on the efflciency of the oil seal between piston and cylinder. In the present instance. this seal is obtained by three sealing rings R, R and R" made according to our invention.

Ring R is seated in a groove 9 at the high pressure end of the piston, while rings R and R" follow in order and are seated in grooves a and g" respectively. Each of the rings is of composite construction in'that it is formed of both spring metal and rubber or its equivalent. We shall describe them inorder.

Ring R (Figures 2, 3 and 4) has a rubber component I, T-shaped in cross section with its flange 2 extending outwardly from the center of its base 3. Shoulders 4, 4 are thus provided to receive helical, spring steel (or plastic) rings 5, 5 of two coils each. The ends I, I of the respective coils are spaced circumferentially and the plane and the two coils in parallel planes. To this extent the rings 5, 5 are not truly helical as what would normally be the pitch of the helix is accumulated in the oiIset 8. However, the winding and unwinding action of the helical spring is retained together with its circularity while either in contracted or expanded condition. This constant circularity of coils insures that the rings 5, 5 will contact the cylinder C snugly and with uniform pressure even as they expand and contract under slight imperfections and irregularities in the contour of the cylinder wall. Obviously, the rings 5, 5gare under tension in the cylinder. The rings 5, 5 fit snugly on shoulders I, I and :against flange 2 of rubber component I, and the assembled ring R is slightly deeper radially than groove g so that it will expand laterally in the groove when confined within the cylinder. In order to permit this expansion, a series of circumferential V-shaped grooves 9, 9 are provided on the inside surface of rubber component I, and the inner marginal edges I ll, I ll of said component are beveled (Figure 4) Since the diametrically expanding action of helical rings 5, 5 cause them to adhere closely to the cylinder wall and'the lateral expanding action of the rubber component I causes said rings to adhere closely to the sides of groove g. there is little opportunity for oil to leak past the piston P as it is operated back and forth in its cylinder C.

Y The inside diameter of the ring component i is slightly less than the diameter of the bottom of groove 9 and the width across the base 3 is slightly less than the width of the groove so that whenthe ring component is placed in the groove,

- it will be circumferentially stretched and will part of the helix between the coils has a slight tightly hug the groove bottom. Thus the component I is always under compression between the bottom of the groove g and the cylinder wall. The steel or plastic ring components 5, 5 not only operate as oil scraper rings during the travel of piston P, but alsoprotec-t the component I from damage by impact against the sides of the groove during the piston action and collapse under use.

In the modification shown in Figure 5, the rubber component 2 is embraced by one coiled component Ii and one plain split ring l2, while in the modification of Figure 6, two plain split rings l3, l3; Obviously. many different combinations are possible under our invention. a 1

Having described our invention, we claim:

A piston ring comprising an endless annular component of rubber (or equivalent material) of T-shape cross section, a pair of annular spring elements disposed in intimate contact with the 3 '4 sides or the flange of tlze 1rl'ubber component, and UNITED STATES PATENTS said rubber componen avlns circumferential grooves on its inner cylindrical surflwe. and said 2%;? g? Jan 5 spring elements being or the order of a helix to 1:612o39 Miner 1926 permlt expansion and contraction without loss of 5 2,019,757 Lowek N v 935 clrcularlty 1 233,2? Marlen Aug. 30, 1938 FRI 0 Balach July 23, 1940 fi fivm w; 3 Jackman May 16, 1944 REFERENCES crnm I FOREIGN 5 Number I Country Date The following references are of record in the 523,024 England June 6 19 file of this patent: I r 551,507 England Feb. 25, 1943 

